Optical Engine Including Fiber Deflection Unit and Method Forming the Same

Abstract

A method includes forming an optical engine, which includes a photonic die. The photonic die further includes a grating coupler. The method further includes forming a fiber unit including a fiber platform having a groove, and an optical fiber attached to the fiber platform. The optical fiber extends into the groove. The fiber platform further includes a reflector. The fiber unit is attached to the optical engine, and the reflector is configured to deflect a light beam, so that the light beam emitted by a first one of the optical fiber and the grating coupler is received by a second one of the optical fiber and the grating coupler.

What is claimed is: 
     
         1 . A method comprising:
 forming an optical engine comprising a photonic die, wherein the photonic die comprises a grating coupler;   forming a fiber unit comprising:
 a fiber platform comprising a groove; 
 an optical fiber attached to the fiber platform, wherein the optical fiber extends into the groove; and 
 a reflector; and 
   attaching the fiber unit to the optical engine, wherein the reflector is configured to deflect a light beam, so that the light beam emitted by a first one of the optical fiber and the grating coupler is received by a second one of the optical fiber and the grating coupler.   
     
     
         2 . The method of  claim 1 , wherein the forming the optical engine comprises bonding a supporting substrate to the photonic die, wherein the supporting substrate comprises a first lens configured to converge the light beam. 
     
     
         3 . The method of  claim 2 , wherein a first center of the first lens is laterally offset from a second center of the reflector. 
     
     
         4 . The method of  claim 2 , wherein the supporting substrate further comprises a second lens configured to converge the light beam, wherein the first lens and the second lens are on opposite sides of the supporting substrate. 
     
     
         5 . The method of  claim 1 , wherein the forming the photonic die comprises:
 patterning a top silicon layer in a substrate to form a plurality of photonic devices, wherein the substrate comprises the top silicon layer, a first dielectric layer under the top silicon layer, and a semiconductor layer under the first dielectric layer;   forming a second dielectric layer to embed the plurality of photonic devices therein;   forming an interconnect structure over and signally coupling to the plurality of photonic devices; and   bonding an electronic die to the interconnect structure.   
     
     
         6 . The method of  claim 5  further comprising:
 removing the first dielectric layer and the semiconductor layer; 
 forming backside dielectric layers and waveguides in the backside dielectric layers; and 
 forming through-vias penetrating through the backside dielectric layers to electrically couple to the interconnect structure. 
 
     
     
         7 . The method of  claim 1 , wherein the fiber unit comprises a lens located in a light path of the light beam, and wherein the lens is configured to converge the light beam. 
     
     
         8 . The method of  claim 1 , wherein the reflector is curved. 
     
     
         9 . The method of  claim 8 , wherein the reflector fits a circle in a cross-sectional view of the fiber unit. 
     
     
         10 . The method of  claim 1 , wherein the reflector is planar-and-tilted. 
     
     
         11 . The method of  claim 1 , wherein the fiber unit comprises:
 a plurality of grooves, with the groove being one of the plurality of grooves; and   a plurality of optical fibers extending into the plurality of grooves, with the optical fiber being one of the plurality of optical fibers.   
     
     
         12 . The method of  claim 1 , wherein the attaching the fiber unit to the optical engine comprises attaching the fiber unit to a supporting substrate in the optical engine, wherein the fiber unit is further attached to a metal lid that encircles the optical engine, and wherein the fiber unit extends into an opening in the metal lid. 
     
     
         13 . A package comprising:
 a photonic die comprising a grating coupler;   a supporting substrate over the photonic die, wherein the supporting substrate comprises a first lens; and   a fiber deflection unit attached to the supporting substrate, wherein the fiber deflection unit comprises:
 a fiber platform; 
 a reflector on a sidewall of the fiber platform; 
 a groove in the fiber platform; and 
 an optical fiber extending into the groove. 
   
     
     
         14 . The package of  claim 13 , wherein the reflector is configured to deflect a light beam emitted from the optical fiber and traveling in a horizontal direction to a vertical direction and to the grating coupler. 
     
     
         15 . The package of  claim 13 , wherein the reflector is configured to deflect a light beam emitted from the grating coupler and traveling in a vertical direction to a horizontal direction and to the optical fiber. 
     
     
         16 . The package of  claim 13 , wherein the reflector is curved. 
     
     
         17 . The package of  claim 13 , wherein the reflector is straight-and-slanted. 
     
     
         18 . A package comprising:
 an optical engine comprising:
 a photonic device; and 
 a lens over the photonic device; 
   a metal lid, wherein the optical engine is covered by a top portion of the metal lid; and   a fiber deflection unit extending partially into the metal lid, wherein the fiber deflection unit is configured to:
 emit a light beam horizontally out of an optical fiber in the fiber deflection unit; and 
 deflect the light beam to the lens, wherein the light beam is further projected to the photonic device. 
   
     
     
         19 . The package of  claim 18 , wherein the fiber deflection unit comprises a reflector for deflecting the light beam, and wherein the reflector comprises a metal, and has a curved shape. 
     
     
         20 . The package of  claim 18 , wherein the optical engine comprises:
 a photonic die; and   a supporting substrate over and bonding to the photonic die, wherein the lens is in the supporting substrate.